Electronic control devices (e.g., an electro-pneumatic controller, programmable controllers, analog control circuits, etc.) are typically used to control process control devices (e.g., control valves, pumps, dampers, etc.). These electronic control devices cause a specified operation of the process control devices. For purposes of safety, cost efficiency, and reliability, many well-known diaphragm-type or piston-type pneumatic actuators are used to actuate process control devices and are typically coupled to the overall process control system via an electro-pneumatic controller. Electro-pneumatic controllers are usually configured to receive one or more control signals and convert those control signals into a pressure provided to a pneumatic actuator to cause a desired operation of the process control device coupled to the pneumatic actuator. For example, if a process control routine requires a pneumatically-actuated valve to pass a greater volume of a process fluid, the magnitude of the control signal applied to an electro-pneumatic controller associated with the valve may be increased (e.g., from 10 milliamps (mA) to 15 mA in a case where the electro-pneumatic controller is configured to receive a 4-20 mA control signal).
Electro-pneumatic controllers typically use a feedback signal generated by a feedback sensing system or element (e.g., a position sensor) that senses or detects an operational response of a pneumatically-actuated control device. For example, in the case of a pneumatically-actuated valve, the feedback signal may correspond to the position of the valve as measured or determined by a position sensor. The electro-pneumatic controller compares the feedback signal to a desired set-point or control signal and utilizes a position control process to generate a drive value based on (e.g., a difference between) the feedback signal and the control signal. This drive value corresponds to a pressure to be provided to the pneumatic actuator to achieve a desired operation of the control device (e.g., a desired position of a valve) coupled to the pneumatic actuator.